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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Posted on 2 March 2010 by John Cook

The Skeptical Science list of skeptic arguments is one of the larger compilations going around, currently numbering 91 different arguments. However, this is only the tip of the iceberg. Whenever I encounter a skeptic argument, I add it to the database which currently contains 242 skeptic arguments. The 91 are those which I've found the time to research and write a summary of what the peer-reviewed science says on the topic. Now all 242 arguments have been categorised and displayed on a new Global Warming Links page. And just to open up a potentially huge can of worms, you can add to the list of skeptic arguments yourself!

There's more to this list than just the skeptic arguments. Besides each skeptic argument, you'll notice a green and red number. The green number denotes the number of web pages about that skeptic argument that endorse man-made global warming (let's call them pro-AGW). The red number denotes the number of skeptic links. This is the guts of Global Warming Links - a resource of global warming links expressing both sides of the debate.

Sometimes Skeptical Science is accused of being unbalanced. This criticism is certainly true in terms of the links collected so far. There are substantially more skeptic than pro-AGW links. This is because I've been collecting skeptic links for years, since before I started Skeptical Science. However, I've only been collecting pro-AGW links since I started developing the Links page a few weeks ago. So I would encourage anyone if they encounter a webpage or blog post about a particular skeptic argument to submit it in the Add New Link form.

I've also added two other interesting pages which are linked to from the top of Global Warming Links. There's Last Week which lists the most popular skeptic arguments submitted over the last week. This should be useful for keeping track of the latest, most popular skeptic arguments. The problem is currently there are only a handful of articles submitted over the last week so it's not a terribly comprehensive representation yet. Hopefully the list will fill up in quick time. There is also Last Month which lasts the most used skeptic arguments over the last 30 days.

Even while developing the Links page, I've found it an immensely handy resource. Whenever I encounter an informative webpage addressing a specific skeptic argument, I quickly go to Add New Link and submit the URL. That way, it's filed away for future reference, categorised and ready at my fingertips. My hope is that as the directory fills up with links, when people need to research a particular argument, they'll have a collection of useful links all gathered in the one place focused on the topic at hand.

Of course, the reason I'm doing this is because a single person can't keep track of every skeptic argument ever used. So I'm hoping Skeptical Science readers will over time help build a comprehensive list of arguments and links. Giving the online community access to my database, meticulously and lovingly constructed for years, is not an easy step for a control freak such as myself. So it goes without saying that the submissions will be moderated - both arguments and links. Any user caught spamming or submitting frivolous arguments or links will have their user account disabled. But if you submit proper links, your contribution will be very much appreciated. Remember, both skeptic and pro-AGW links are welcome.

UPDATE: to make the Links page easier to get to, the LINKS navigation in the header now links to the Links page. The old links page can now be reached via a link at the bottom of each page.

Comments

This is so absolutely brilliant I don't even know how to express it! You're getting some money from me right now to support this important project. (I'm not rich, but happen to have a few bucks stacked away at a PayPal account donated to me for a far more silly project. I know from this experience that if a whole bunch of people donate $5 each, it can pay your rent.)

Have you added your argument to the list yet? If not, I'll be happy to do it. While an entire post can be dedicated to the topic, the short answer to your comment is that AGW is easy to attack. You simply need to prove that anthropogenic emissions are not able to cause an increase in global temperatures.

Why no links to the IPCC report? Every section of the IPCC report has its own webpage. A quick glance at your list of items and seeing all those green zeros got me repeatedly saying to myself "that's answered somewhere in the IPCC report." Can we start adding those?

00

Response: Yes please, and it would be great if you could link to the HTML version of the IPCC 4th Assessment Report rather than the PDFs. The HTML version breaks up each section into its own webpage with a narrow focus whereas the PDFs contain entire chapters in the one document. Adding this would be an extremely useful resource.

I have just added my first couple of links (refuting the disgraceful and unfounded accusations made about New Zealand temperatures). I will be adding more when I have time.

It will be interesting to see how Skeptical Science develops from now on. I have been coming here for a few months now and rate it very highly. It does seem to have really taken off recently and I hope you are able to cope with all the extra work that the additional visitors entail (I will donate when I am able - I certainly owe you) and aren't swamped by trolls and other negative and destructive individuals. Keep up the good work.

Hmmm... should we include arguments which make no attempt at putting a 'scientific' veneer on it?

For instance, 'God would not allow us to damage his creation', 'God promised he would not make another Great Flood', or 'It is sinful arrogance to think that we could upset God's plan'. Et cetera.

As the apparent purpose of the list is to accumulate actual evidence for and against various positions I'd question whether arguments which are overtly 'faith based' really fit the mold. Short of some sort of theological debate (i.e. 'God said that HE would not cause another Great Flood, but that does not mean WE cannot') there isn't really much 'evidence' to gather one way or the other.

I just added a new argument below "it hasn't warmed since 1998) when I meant to add a link to an existing argument (which I thendid correctly). Please delete it. (As a software developer, I blame the tech writers for not being clear enough in the instructions!)

00

Response: Fair criticism, I will endeavour to clarify instructions in the submission forms as I see what common errors are made. I've deleted that submission so I suggest resubmitting as a link.

In this discussion, we again encounter the vexing problem of finding appropriate terms to describe the opposing "camps" in the debate over AGW. (Even the term "AGW" is problematic!!)

"Pro-AGW" is intended to convey concurrence with the predominant scientific interpretation that anthropogenic greenhouse gases are causing enhanced warming of the Earth's surface. Unfortunately, "pro-AGW" inadvertently conveys bias, whereas this position is actually rooted in sound scientific evidence and reasoning. Admittedly, some who concur with AGW do so on the basis of faith or prejudice, and are equally as dogmatic as many of those who reject AGW.

On the other side, the term "skepticism" has its own limitations. The Greek root "skepsis" conveys inquiry, examination, or thought. The word skepticism has come to convey doubt or uncertainty toward particular views. Historically, skepticism was intended to challenge "dogmatism", which represents an inflexible, unthinking certainty in one's views.

Skepticism is now regarded as a required element of the scientific method, as science-based conclusions are in perpetual need of revision and refinement. Doubt, thought, and inquiry are essential for this process to be successful. In actual practice in the AGW debate, however, there is commonly little actual thought and effectively no doubt associated with the rejection of AGW. Too often this position is not truly skeptical but dogmatic, and is rooted in politics and ideology, not in science. Being rooted in politics, it is often laden with emotionalism as well.

Some people (myself included) have used the term "Denialism" to describe this position. AGW Denialism presumes that AGW is wrong, then specifically seeks out evidence consistent with this presumption, while summarily rejecting evidence inconsistent with it. The down side of the term Denialism is that it is unfair to actual AGW skeptics (even if they be few in number). Moreover, skeptics and denialists alike find the term "Denialism" offensive, so it's a nonstarter if we are to retain any hope for dialogue.

The term "Rejects AGW" conveys some process of reasoning, even if it is tainted by bias. It also has the advantage of being more descriptive and less judgmental. The term "Accepts AGW" conveys a conclusion that could be the result of a rational, science-based reasoning, but could encompass faith-based acceptance as well.

Unfortunately, the terms "Accepts AGW" or "Rejects AGW" are awkward to apply.

More and more I'm inclined to apply the term "rejectionist" to generally describe folks who don't seem to be able to integrate facts in a coherent way leading to a useful argument countering our accepted understanding of how our climate functions.

It's easily possible to generalize too much. I think Berényi Péter who frequently posts here with reasoned arguments backed up with numerical treatments is a close approximation to a skeptic in the traditional sense. This fellow is capable of concession, a key diagnostic of reasonable behavior.

Another species are the cynics, speculating bad motivations on the part of researchers, but they share in common with rejectionists that they are not able to produce a robust argument justifying their position.

We have such a rich language in English, stolen from many sources and with wonderful granularity. It's worth exploiting, even if only to avoid monotony.

Why not utilize the names that groups call themselves, and then argue the merits of the discussion rather than utilizing connotative naming conventions that reveal the bias of the user?

As an example....although possibly accurate, use of the term homosexual has become unacceptable since members of that group have rejected the moniker and now wish the term "gay" to be used for their group.

In much the way that using the term homosexual would reveal bias from the user, use of terms such as "alarmists", "deniers", and "rejectionist" reveals the bias of the user.

It seems reasonable to say that if you disagree with any particular research finding, your appropriate pigeonhole will depend on how effectively you express your disagreement.

So, w/regard to C02 sensitivity, your particular label will depend on if you can cite or make a coherent argument for your assertion that IPCC is overestimating sensitivity, as opposed to simply saying "I don't believe it."

"What's the term for those of us who agree the CO2 is a greenhouse gas, but believe that the IPCC estimates of climate sensitivity are off by at least a factor of 2?"

Classical Climate Scientists? :)

Didn't Svante Arrhenius provide the first estimate of climate sensitivity in 1896? Arrhenius was part of the move from classical to modern physics, and was one of the first Nobelists, so I think the name fits.

He proposed (I believe) 4-6C, which is now considered too high by about 1C, not "by a factor of 2". What was wrong with his estimate? Only askin'.

Some people believe that skepticism is the rejection of new ideas, or worse, they confuse “skeptic” with “cynic” and think that skeptics are a bunch of grumpy curmudgeons unwilling to accept any claim that challenges the status quo. This is wrong. Skepticism is a provisional approach to claims. It is the application of reason to any and all ideas — no sacred cows allowed. In other words, skepticism is a method, not a position. Ideally, skeptics do not go into an investigation closed to the possibility that a phenomenon might be real or that a claim might be true. When we say we are “skeptical,” we mean that we must see compelling evidence before we believe.

It's difficult to find a formal definition of AGW, as it’s more of a vernacular term than a scientific term. The phrase “global warming” is neither defined nor used by the IPCC. In practice, however, AGW refers comprehensively to the interpreted human impact(s) on climate, including an increase in globally averaged temperatures. More specifically AGW describes warming of the Earth's surface due to enhanced retention of solar energy by anthropogenic greenhouse gases, especially CO2. (That is, GHGs added to the atmosphere by, or related to, human activity). A substantial proportion of the retained energy, however, goes toward melting ice and warming of the deep ocean, which may not be manifested in surface temperatures.

Despite its limitations, the term AGW is useful because it is succinct and widely recognized. It is, nevertheless, potentially subject to misunderstanding and misuse. For example, some AGW "rejectionists" (TOTH to doug_bostrom!) use the term “global warming” to refer to non-anthropogenic warming occurring since the last glacial maximum (around 22,000 years BP), or to the slight warming observed in some regions following the (loosely defined) "Little Ice Age". This apparently intentional misuse of terminology sows confusion, not understanding.

Karl_from_Wylie at #17:
Nice notion, but impractical. I’m all for avoiding epithets, but unfortunately there’s no consensus how this group would like to be called. In a classic interview on The Weather Channel, Fred Singer proudly lays claim to being called a "skeptic", but then ends the interview by stating that he has no doubts that he may be wrong in rejecting AGW. Hmmmmm…. Many even dislike the term "skeptic", preferring instead to be called "Realists"! (No chance of my using THAT term!).

The terms "rejectionist" or "denialist" are descriptors, and not necessarily intended as epithets. After all, were it not for rejection of theory of AGW and the threat it is inferred to pose to "quality of life", most of the non-climate scientists comprising this group would have no more opinion on attribution of climate change than they would on their favorite flavor of quarks! Rejection (or denial) of AGW is the sine qua non of this position, and "dancing around" this in an effort to protect sensibilities can be awkward at times.

Tobyjoyce "He proposed (I believe) 4-6C, which is now considered too high by about 1C, not "by a factor of 2". What was wrong with his estimate? Only askin'."

He later revised his estimate to 1.6C for a doubling of CO2 in his 1906 paper.

I agree with that as the starting point for doubling CO2. I also agree that CO2 is now approaching 390ppm from a level back in 1700's and 1800's of around 275ppm. 390/275=sqr(2), so since the CO2 effect is logarithmic, the expected effect from Arrhenius's 1906 calculations using today's CO2 number would be about 0.8C rise.

Now the discussion goes to how much feedback is in the climate system and whether it is positive or negative feedback. IPCC comes up with significantly positive feedback, based primarily upon modeling as opposed to analysis of empirical data.

I tried to submit a new skeptic argument, but it wouldn't let me unless I selected a parent argument, and none of the parent arguement options was right. So I'll do it here instead. It is one I ran across the other day:

"Over geological time, there is no consistent correlation between CO2 and temperature"

It is at this link:
http://sbvor.blogspot.com/2009/10/climate-change-science-overview.html

This is an absolutely fantastic idea John. I salute you sir, and will be back with arguments, and links as I find them. Lets create a proper database!

00

Response: Yes, it is imperative to select a parent argument in order to keep it all organised and categorised. The parent argument for yours would be "there's no correlation between CO2 and temperature". This is a good suggested argument actually - the "no correlation" argument is more general and tends to be applied towards the 20th Century so a focus on more geological time periods is a good idea.

Please do continue to add arguments and links - it would be very handy for many people if we could build this into a useful and hopefully eventually comprehensive resource.

John,
How about adding a comments section to each of the Arguments so that individuals (see all those above) can add their own thoughts.
Any way to alphabetize them? or otherwise rank them in popularity? Sorting capability?

00

Response: Currently they're ordered newest to oldest which I find useful for looking at the latest submissions. However, I'll probably add an ordering feature allowing you to order by date, alphabetically and if I feel really energetic, I might even add a ranking feature so most popular ones rise to the top.

Comments? Hmm, will think about this one. It's tough enough keeping track of all the comments on the blog posts and skeptic arguments.

"Arrhenius estimated that halving of CO2 would decrease temperatures by 4 - 5 °C (Celsius) and a doubling of CO2 would cause a temperature rise of 5 - 6 °C[4]. In his 1906 publication, Arrhenius adjusted the value downwards to 1.6 °C (including water vapour feedback: 2.1 °C). Recent (2007) estimates from IPCC say this value (the Climate sensitivity) is likely to be between 2 and 4.5 °C"

Given that 0.5-1C is what is generally accepted for global average temperature rise up until now, and you agree with a climate sensitivity close to the low end of the IPCC estimate, I find it hard to see how you label yourself "sceptic". From my own reading, I do not recall any reported instances of negative climate feedback ... where have you seen that evidence?

I don't accept the distinction between "models" and "empirical data" ... all empirical data has to go into some kind of black box (no matter what science). For acceptance, what comes out must in some manner be consistent with the initial hypothesis (represented by a different set of empirical observations), to within some degree of statistical significance. You will find every sceptic paper also has a model, or find me one that does not!

IPCC comes up with significantly positive feedback, based primarily upon modeling as opposed to analysis of empirical data.

Corroborated by empirical obs and analysis of ice age changes. A weak change (>10%) in insolation at the surface at one pole (with the opposite change at the other) produces a world-wide climatic shift of 5C. If it weren't for well-mixed, rising GHGs, the heat would not be transported so evenly, and if there weren't strong feedbacks to forcings, we wouldn't have ice ages.

barry at 09:53 AM on 3 March, 2010 " A weak change (>10%) in insolation at the surface at one pole (with the opposite change at the other) produces a world-wide climatic shift of 5C. If it weren't for well-mixed, rising GHGs, the heat would not be transported so evenly,..."

Are you saying that well mixed greenhouse gases have a significant effect on hemisphere to hemisphere transport of heat ???

tobyjoyce at 09:51 AM on 3 March, 2010 "From my own reading, I do not recall any reported instances of negative climate feedback ... where have you seen that evidence?"

Many climate scientists have noted that clouds provide both positive and negative feedback. IPCC also lists the effects of clouds as one of the biggest uncertainties in climate science.

Indeed, the recent work by Willis Eschenbach is related to the daily variation in clouds very common in the tropics. Low clouds form in the late morning, often turning into thunderstorms in late afternoon, and then clearing around sunset.

Several effects are at work. A low cloud generally is a positive feedback in that it adds to the greenhouse effect. But a low cloud also increases albedo. At local noon, a low cloud is an overall negative feedback. At night, it is clearly positive. So the phasing of diurnal cloud formation with respect to local noon affects the overall feedback.

Cumulonibmus clouds have the additional effect of heat transport upward above a sizable fraction of the lower atmosphere water vapor and other GHGs.

The Heat From a Global Warming Column
http://www.washingtonpost.com/wp-dyn/content/article/2009/02/27/AR2009022702334.html

is listed under "skeptic links" for "there is no consensus", but it's by the Washington Post's ombudsman acknowledging that a column by denier George Will contains significant errors. It might rather go into the "pro-AGW" list.

Charlie A,
the good old iris hypothesis is not supported by Lindzen itself anymore (beyond being contradicted by observations).
Having said this, the problem of cloud feedback is a complicated one and can not be treated so easily on the basis of suppositions, local effect, one type of cloud, etc., the overall effect of warming must be addressed.

John - the Venus thing is commenter Bob Armstrong's thing, but he's not the original source for it. He says, and I quote, "Also notable is that the temperature of Venus, commonly cited as what "runaway" warming could do to us, is twice as hot as the sun can possibly heat any object in its orbit. That is, Venus must have some internal source of heat because it is radiating much more energy than it is receiving from the sun."

I've disproven this mathematically, but haven't had a chance to write it up as a post at scholarsandrogues.com yet. Too many equations, and I haven't found a good way to create equations for HTML yet.

I think the problem Josie is encountering may be that the scroll bar is off the right side of the page. Thus, only the top of the argument list is shown and there is no clear indication that more arguments are available below. I ran into this myself, but was able to get around it using the arrow keys to move up and down through the list.

00

Response: Okay, I see the problem - in Firefox, the dropdown extends beyond the right side of the page. This doesn't happen in Internet Explorer. I'm looking into fixing this right now. I seriously have to stop using IE so exclusively!

Not too sure every link can be described as either "pro-AGW" or "skeptic", but I understand why you have done that...

Under the "better to geoengineer" section I added a link to My MSc dissertation which examines the prospects for reversing dangerous global warming by directly capturing CO2 from the atmosphere ("dangerous" being defined as >2 degrees above pre-industrial temperature). It contains some back of the envelope estimates which gives some idea of the sheer scale and cost of the operation that would be needed to even reduce the atmospheric CO2 concentration by 150ppm (say from 500ppm to 350ppm), we are talking about capturing and storing over a trillion tonnes of CO2! It is theoretically possible but it would require an enormous global engineering effort, at best it would take many decades to achieve and it would cost many trillions of dollars... it's certainly not an alternative to making emissions cuts (but it may be needed IN ADDITION to severe emissions cuts if climate sensitivity turns out to be at the high of the estimate).

Geoengineering solutions that block incoming solar radiation could be potentially as dangerous as AGW and are fraught with political problems (who controls them and who decides at what stage they should be used etc).

00

Response: I will get around to adding Neutral as an option sooner or later.

I saw your paper on capturing CO2 and thought it very interesting. The prospect of capturing 150ppm is an exciting idea and I hope it is a practical proposition. I think it's inevitable that these kinds of solutions are explored in upcoming decades - you better get in at the grass-roots level :-)

66. MWP. Weak argument. Although evidence is sparse I think there is good enough evidence that it was global.

70. Phil Jones. This is absolutely correct but begs the question if the warming is so insignificant then what is the problem?

78. CO2 being the main driver of climate. No evidence just a presumption.

80. Its not happening - looks like a strawman, but I am not even sure I what it means. Do you think that skeptics say the climate does not change?

83. CO2 is not increasing - sorry, who says this? Strawman argument.

89. Tree rings. This does not adequately cover the point at all. If tree rings in the samples used diverges after 1960s it means that they are highly ineffective proxies before that. You only need one car crash to show you have a faulty car (Toyota).

Question - have you left out clouds on purpose or do you feel it is in there as water vapour and albedo effect?

Observation: your tone is to support climate change science and AGW whatever the counter argument which as I said before makes it look more like a belief than a 'skeptical about skeptics' argument.

Yocta, I would not bother with TL at deltoid, they maintain a certain level of hysteria which is entertaining but does not advance any discussion. They guy is happy to do a bit of dissembling himself (see http://scienceblogs.com/deltoid/2010/02/moncktons_mcluhan_moment.php)

There has been recent work in addressing the “Divergance Problem” in tree ring data. Considering the public scrutiny on this due to the hacked CRU e-mails, and the critical attacks on previous IPCC representations of tree ring data in particular, it is topical and pertinent. I would be interested if others know of parallel or even contradictory work.

Divergence pitfalls in tree-ring research (Esper and Frank, 2009)

http://www.springerlink.com/content/873486u687j56246/fulltext.pdf Which refers to the following recent key work in its conclusion:

Testing for tree-ring divergence in the European Alps (Buntgen 2008)

http://www.st-andrews.ac.uk/~rjsw/all%20pdfs/Buntgenetal2008.pdf

(Extract from abstract) Tree-ring width chronologies from 40 larch and 24 spruce sites were selected based on their correlation with early (1864–1933) instrumental temperatures to assess their ability of tracking recent (1934–2003) temperature variations. After the tree-ring series of both species were detrended in a manner that allows low-frequency variations to be preserved and scaled against summer temperatures, no unusual late 20th century DP is found. Independent tree-ring width and density evidence for unprecedented late 20th century temperatures with respect to the past millennium further reinforces our results.

An excellent resource for anyone interested in evidence of climate change from tree ring data is Buntgens homepage and the following (rather nice) links in particular. The graphs speak volumes.

The challenge will be to keep a good hierarchy of arguments. That's the value of it now. Great job.

00

Response: Thanks, Steve, I had thought your very informative pages would be a welcome resource so if you're adding them in, that's much appreciated (and I believe of much benefit to those perusing the list of arguments).

Si, at #48:
The goal of the skepticalscience.com site is to inform readers of the scientific evidence for climate change. The links you provided are not helpful in this regard (nor do they provide "light relief"), because the very real decline in Arctic sea ice cover is very difficult to discern. The following graphic shows the trend far more clearly:
http://nsidc.org/images/arcticseaicenews/20100303_Figure3.png

John provides several other helpful links in his post:
http://www.skepticalscience.com/Arctic-sea-ice-melt-natural-or-man-made.htm

The videos are particularly sobering, showing the flushing of old sea ice from the Arctic Ocean. (It's all gone, now, by the way... the old sea ice, that is.)
http://www.youtube.com/watch?v=Co68_tod0dQ

Ok, so repeating some comments I made on Facebook regarding this very cool project:

1. It would be nice if there was a field for language. I'd like to keep track of articles on Swedish press, and what arguments they use, so why not use this tool - but I wouldn't want to clutter the list for non-Swedish readers.

2. I think it also could be useful with a field to classify sources in categories such as "mainstream media" and "blogs", or such. The reason is that if that you're going to cover the whole denialist blogosphere, it's going to get unwieldy, and someone might be interested in just seeing how arguments are used in regular media. But maybe it's better to wait and see how it turns out.